Proto is the protocol used. tcp and udp should be pretty self-explanatory. icm is short for ICMP, which is a network control protocol (pings use ICMP echo/reply messages). The number at the end specifies if it's IPv4 or IPv6

Recv-Q and Send-Q are the receiving and sending queues. If those aren't zero, you're either sending much faster than the other side can read, or you're not reading fast enough yourself.

Local Address is the local IP and port used, while Foreign Address is the remote site and port.

State is the state (duh) of the connection. LISTEN means there's a local server listening, ESTABLISHED ...well should be clear, CLOSE_WAIT means you're waiting for confirmation that the connection can be closed. For more details, read up on the TCP protocol.

The second part are UNIX domain sockets, which are a kind of IPC, acting like a network socket.

The Address is the memory address used

The queues mean pretty much the same as above

The Inode is just that. In keeping with "everything is a file", UNIX sockets can be addressed via the respective inode on the filesystem